From the Director

Rex

 

 

 

by Rex Parker, Director

Dark Skies, Our Eyes, and Outdoor Lighting.
Nearly three-fourths of all Americans reside under skies where the Milky Way is not visible. It’s natural as we age to lose some night sky acuity, as our upcoming guest lecturer, author James Chen, will discuss on November 14 (see the section by Program Chair Ira Polans in this issue). But in addition to aging eyes, worsening light pollution translates to further loss of night vision especially in NJ and the northeast. Among several aspects to this issue, one that I want to bring to your attention is skyglow, the increased sky brightness arising from light scattered by aerosols and molecules in the atmosphere.

Initial optimism for replacing outdoor lighting fixtures with energy efficient solid state LED luminaires, originally thought to reduce light pollution, has recently turned to concern within the astronomy community. As installation of the new LED technology expands around the country, it has become apparent that the relatively blue-rich LED spectrum actually worsens visual skyglow. This unfortunately diminishes the ability of the dark-adapted eye to see stars and the Milky Way, and worsens the contrast of faint deep sky objects in telescopes. Compared to the yellow-shifted emission spectra of the historically most used lighting fixtures, high or low pressure sodium vapor, the adverse effects of blue-rich LEDs are an ominous new threat to our remaining natural night skies.

This emerging well-intentioned effort to replace older outdoor lighting fixtures with newer LED lighting is going to make our astronomical lives more difficult because of the shift in light source spectrum. Most of the discussion about these light sources concerns their favorable electricity usage and profile for normal light adapted (photopic) vision, which is physiologically distinct from night (scotopic) vision. Scotopic vision is dependent on the eye retina’s rod cells which are sensitive to shorter wavelengths of light (blue to green) and insensitive to longer wavelengths (red). This is why light sources richer in short wavelengths stimulate our dark adapted vision and make artificial sky luminance we perceive as skyglow. A recent report by US Naval Observatory astronomer Christian Luginbuhl describes this situation in depth (Journal of Quantitative Spectroscopy & Radiative Transfer 2014, 139: 21–26.) Another good discussion of the topic including several spectrum examples of the various lighting types can found here: http://www.flagstaffdarkskies.org/for-wonks/lamp-spectrum-light-pollution/.

One solution to the problem is to promote a change to yellow/amber-filtered LED sources, which are becoming available from manufacturers. I urge AAAP members to become more informed by reading up on these complex issues and spreading the message to use amber filtered LEDs whenever possible, while there is still a chance to make widespread changes.

Skynet Update. Taking other steps to mitigate skyglow and loss of night vision, to date 26 members have requested Skynet accounts, and 9 of us have taken images with the Skynet robotic telescope network. Our arrangement with the University of North Carolina, Chapel Hill, Physics and Astronomy Dept, provides remote astrophotography access using state of the art telescopes, mounts, and CCD cameras and software. The instruments are located at observatories spanning the globe. This is an exclusive benefit of AAAP membership, as we seek to gauge interest among members for deeper learning about astro-imaging technologies and approaches. If you’re interested but haven’t yet taken the plunge, send me an e-mail note and I’ll provide you with an account to log-in to the system.

Mark Your Calendar for Next Year’s StarQuest. At last month’s meeting we voted to continue the Jersey StarQuest tradition next year. We’ve reserved Oct 5-6, 2018 at Hope Center in north Jersey where the effects of light pollution are less than around Princeton. The deep sky observing conditions at Starquest-2017 last month were among the best we’ve had in New Jersey, reminding us why we pursue such a challenging avocation as seeing faint, distant galaxies and nebulae with our own equipment through our own eyes!

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From the Program Chair

By Ira Polans

James Chen

The November AAAP meeting will be held on the 14th at 7:30PM in Peyton Hall on the Princeton University campus. The talk is by James Chen on his book “Astronomy for Older Eyes”. This month we are introducing a new format to the meetings. After the Rex’ introductory comments one of our members will give a 10 minute talk on an astronomy related topic. This will be followed by the guest speaker’s presentation. Then there will be the regular break followed by the business meeting.

Jim Chen’s book is for the aging amateur astronomy population, including newcomers to astronomy in their retirement and hobbyists who loved peering through a telescope as a child. Whether a novice or an experienced observer, the practice of astronomy differs over the years. This guide will extend the enjoyment of astronomy well into the Golden Years by addressing topics such as eye and overall health issues, recommendations on telescope equipment, and astronomy-related social activities especially suited for seniors.

Many Baby-Boomers reaching retirement age are seeking new activities, and amateur astronomy is a perfect fit as a leisure time activity. Established backyard astronomers who began their love of astronomy in their youth, meanwhile, may face many physical and mental challenges in continuing their lifelong hobby as they age beyond their 55th birthdays. That perfect telescope purchased when they were thirty years old now suddenly at sixty years old feels like an immovable object in the living room. The 20/20 eyesight has given way to reading glasses or bifocals. Treasured eyepieces feel all wrong.

Growing old is a natural process of life, but astronomy is timeless. With a little knowledge and some lifestyle adjustments, older astronomers can still enjoy backyard observing well into their seventies, eighties and even into their nineties.

During the break James’ book will be available as part of a book signing.

Our first 10 minute talk will be given by Peter Wraight. Peter will talk about two topics “A Different Approach to Building Astronomical Binoculars” and “A Generalized Coordinate and Finder System for Locating Celestial Objects” For the first topic Peter will present binocular designs that attempt to overcome some of the drawbacks of regular binoculars for astronomy. Two examples will be shown: one using 100 mm f/4 objective lenses and the other using 6 inch f/5 mirrors. The second topic is about the Tri-Finder system a fully generalized star reference coordinate system which enables a telescope to be pointed to within 0.5 degrees of any absolute position in the sky by only using two guide stars of 3rd magnitude or brighter. This accuracy is available over the entire sky and is achieved without any specific alignment or precision of the telescope mount.

If you are interested in giving a 10 minute talk at a future meeting please contact me at program@princetonastronomy.org. Please let me know the topic and your availability.

Prior to the meeting there will be a meet-the-speaker dinner at 6PM at Winberie’s in Palmer Square in Princeton. If you’re interested in attending please contact program@princetonastronomy.org no later than Noon on September 12.

If you have suggestions for speakers please send them to program@princetonastronomy.org. Please provide the speaker’s name, topic, and affiliation. Thanks!

We look forward to seeing you at the September meeting and the dinner!

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October 10, 2017 Meeting Minutes

by Jim Poinsett, Secretary

Minutes of the October 2017 Meeting of the AAAP

• Rex called the meeting to order at 7:30

• Two speakers for the evening

    –  Arshad Jiliani showed the video he compiled of the trip to Oregon to view the total eclipse taken by a group of club members. He also answered some questions during a brief Q&A session afterwards.

   –  Rex Parker explained how to sign up and use the club membership to take photos using the Skynet Robotic Telescope Network. It is a free benefit for all club members interested in using it.

• After the break, the first topic discussed was the club sponsored star party, Star Quest. This year was possibly the best weather ever for the event, everyone who was able to attend had a great time. Next years event will be held on the weekend of October 5-6, 2018. A change in pricing will be discussed at the board meeting as the fee charged only covered about 50% of the expense.

• The observatory was the next item discussed. This has been a very good year for the observatory with few weeks to go. The equipment has held up very well.

   –  The Mewlon’s image is less than ideal. It needs to be collimated. Takahashi sells a tool to do this, it is about $400 but would also be adaptable for use on member owned scopes. The board will discuss buying it at the next board meeting.

   –  A discussion was held on the need for better monitor for the video camera. The possibility of needing a higher resolution camera was also brought up as an alternative. Further discussion will be held before the next viewing season.

   –  The topic of security at the observatory was also brought up. With the additional equipment better security is warranted and with the addition of internet access better security is readily available. Several options will be prepared for the board meeting in December.

• The program committee is looking for members to give about a 10 minute presentation at our meetings. Anyone interested in showing or discussing a topic that interests them please let the program chair know.

• There being no more business do discuss, the meeting was adjourned.

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Videos of Total Solar Eclipse taken by AAAP members.

Total Eclipse Story 2017 – by Arshad Jilani

The sky and horizon at totality – submitted by Joy Saxena, shot by Pallavi Narain

Time lapse video of the sky before, during and after totality – submitted by Joy Saxena, shot by Pallavi Narain

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Gravity Waves and the Higgs Boson

by Prasad Ganti

Aerial view of LIGO. Credit - Dailymail

Aerial view of LIGO. Credit – Dailymail

Gravity waves have been in the news for the last two years or so. Firstly, when the hundred year old prediction of Albert Einstein came true. Gravity waves were discovered when two black holes collapsed into one, about a billion light years away. The feeble vibrations of space-time was heard by two well engineered and sensitive detectors called LIGO (Laser Interferometer Gravitational-Wave Observatory). Few more such observations have been made over the last two years. The most recent one resulting from a neutron star collapsing into a neutron star.

When a massive star, tens of times heavier than our Sun dies, it ends up as a neutron star and possibly a black hole. Being so dense and compact, both of them represent gravitational extremities. Neutron stars can be detected by radio and optical telescopes but black holes can only be detected indirectly.

Weiss, Thorne, Barish

Weiss, Thorne, Barish

Upon finding the evidence for a century old prediction by the all time great physicist Einstein, the Nobel prize for Physics in 2017 was awarded to Kip Thorne, Rainer Weiss and Barry Barish for their work on gravity waves. These waves were undetected for a century mainly because they are very very weak. They result from very violent cosmic events like merger of gravitationally intense objects like black holes and neutron stars. These events do not happen frequently in our galaxy. Certainly not in our neighborhood. If they did, we would not exist anymore. Happening at far away distances, the waves travel at the speed of light, and get attenuated on the way to almost the level of insignificance.

Lot of sensitivity in the instrumentation is required to detect such feeble signals. And the noise resulting from other sources needs to be subtracted. Rainer Weiss had analysed the possible sources of background noise that would disturb their measurements. He had also designed a detector, a laser-based interferometer, which would overcome this noise. Basically consisting of two arms in “L” shape running across several miles, with very precise mirrors in both the arms. And a laser beam bouncing back and forth. If there is any disturbance in space-time, the two beams would be out of sync, almost by a whisker. It was necessary to develop new laser technology and invent new materials, as well as construct gigantic vacuum tubes, seismic isolation and other vital technology far beyond what had previously been achieved. Two such detectors were constructed (One in Louisiana and another in Washington state) to eliminate any false alarms resulting from local incidents. Now a third detector in Italy joined the fray.

LIGO. Credit - The Optical Society of America Inc.

LIGO. Credit – The Optical Society of America Inc.

In 1994, when Barry Barish took over as leader for LIGO, he transformed the small research group of about 40 people into a large-scale international collaboration with more than a thousand participants. He searched for the necessary expertise and brought in numerous research groups from many countries. Thus, big science and sophisticated engineering came together. Reminds me very much of the LHC (Large Hadron Collider) in Geneva, Switzerland, which led to the discovery of Higgs Boson, another monumental discovery of this decade. This led to a Nobel prize in Physics to Peter Higgs and Francois Englert in 2013.

Kip Thorne was instrumental in setting up of LIGO. In addition, he was a consultant and an executive producer of the science fiction movie “Interstellar”. The special effects in the movie were pretty close to realty. The graphics team which created the special effects worked very closely with Thorne who worked out several equations to bring a sense of credibility to the imagination. I am glad that Throne won the Nobel prize. Though the prize is not for the movie.

The most recent detection of gravity waves resulted from the collision of two neutron stars. The difference this time being that as soon as the waves were detected, other telescopes and observatories were notified. There was detection of other signals from the same event. Gamma rays were detected by the Fermi observatory in space. Several telescopes detected optical and radio signals as well. It was the first time when multiple scientific devices were able to track a mega cosmic event and study its aftermath.

It is a watershed event in the history of science when such mega projects come together to witness a significant cosmic event, amplifying the human ability to study the cosmos in such detail and depth.

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Fortuna ipsa muta

by Ted Frimet

sheer dumb luck

Not everything is as it seems. And sometimes, despite months or years of amateur training, a gain in insight can be chalked up to “sheer dumb luck”. As most of our AAAP club members are aware, I’ve been hunting an asteroid. And J2012 TC4 came into our field of view, quite nicely in fact, on October 11, 2017 – between the wee GMT hours of 04:01:28.432 and 04:04:38.185. Ten images, at 5 second exposure each, were captured with the Prompt-8 telescope, located at Cerro Tololo Inter-American Observatory, Chile.

APERTURE: 0.6 m
FOCAL LENGTH: 4000.0 mm
F-RATIO: 6.6
FILTERS: B, V, R, I, Red, Green, Blue, Lum, Clear
CCD SIZE: 2048 x 2048 (13 um pixels)
FOV: 23.8 x 23.8 arcmins
SITE: Cerro Tololo Inter-American Observatory

Snippet from skynet robotic telescope network prompt 8 status page, Saturday, October 28, 2017.

The telescope location is at latitude -30:10:3.300’, longitude -70:48:19.200’ (negative means“South”). Why, oh why is he giving us coordinates for his telescope? As I learned, a month before making a Near Earth Object (NEO) observation, the number one thing to remember in Outer Space Real Estate is, “LOCATION, LOCATION, LOCATION’ ! ! !

Sounds easy. Yet, here I am weaving a Saturday morning tale of “woe is to me”, for testing the limits of unknown parameters. I unknowingly ran smack dab into ye old Murphy’s Law. I didn’t know that Murph held title to an NEO. Despite being fenced in by my own mistakes, Murph told me that good fences make good neighbors, and he let me take a peek at the old gal for 10 decent exposures.

What went wrong? Nothing really. That is if you do not count the fact that Skynet – and I must stress – PROPERLY – dispatched my observation requests to sites other than Chile. We took a swing by the R-COP telescope, located at Perth Observatory, Australia, as well as a side-step to the Dark Sky Observatory, DSO-17, in North Carolina, USA. Neither of these observations were validated with an asteroid find. And that, my fellow amateurs, is because the detail lay in the ephemeris data.

I was feeling fresh and all squeaky clean from a visit to NASA’s JPL Horizon database for ephemeris data on our asteroid. I wistfully entered data into the Skynet Robotic Telescope Network Advanced mode. At the time of generating the ephemeris data, I changed my locus to the La Serena site, in Chile, where the Prompt telescopes are given astronomical sanctuary. I made specific requests to match the Right Ascension (RA) and Declination (DEC), gleaned from said ephemeris, right into Skynet, with a matching specified “time of capture equals past mid-night”. I was galavanting past midnight (as my Grandmother would say).

And there’s the rub. Skynet is programmed to direct your request to the next available telescope in your observers list. As I didn’t want to get cheesed out of targeting my asteroid, I left in a healthy dose of alternative ‘scopes. Sans the matching ephemeris data. And that’s when ‘ol Murphy stepped in. If you were imaging stars, your location wouldn’t be quite as critical. However, when you are locating a NEO that is one-tenth Lunar distance from the Earth, your location is important. Ouch. Parallax became the answer to a month long question, as I reviewed, and generated movies for the Australian data, some 6 or 7 times, – leading to negative results.

As I may have mentioned to one or few AAAP members, I do not fear the consequences of failure. I endure, and learn from every miss-step I encounter. I am sure that if I had allowed SkyNet to select my RA/DEC, and automatically reassign to telescopes in waiting, all would have been well. However, my ego got in the way, and I felt that exercising an additional degree of control would be for the better. Nope. I built that fence for Murph, all by myself. “Scored an own”, as the British say. As I found out, a month later, my newest neighbor even tossed in a free doorpost, as the DSO in NC, was of course, not located in a La Serena, observers location.

At the time of this writing, I was planning on establishing tighter magnitude measures of 2012 TC4. I was going to make lemonade out of the lemons of R-COP and DSO-17. The elephant in the room, is of course, parallax and that there is no data to measure in those astro-images.

I am planning to program a course of observations of Algol, a variable star, from minimum to maximum, to map out its magnitude (thanks to John Church, AAAP for pointing out the RASC data on the web). And to compare the results to knowns, so as to establish my own candlestick. And then to revisit the 10 successful images taken by Prompt-8 and re-sample the magnitudes, and make some coarse adjustments. Armed with some self-obtained results, I will be able to compare my magnitudes with the NASA data, and decide if the asteroid is closer to being 15 meters or 28 meters wide. Or perhaps, if it emits more light than predicted (thanks to Gregg Waldron, NWJAA for pointing this out) – that I have proof that 2012 TC4 is a younger asteroid, as opposed to being an old beaten space rock, not unlike my neighbor, ‘ol Murph.

Please note that although hundreds of observations were made of this NEO, there were only two observatories that posted videos that focused primarily on the science of the asteroid. That was the Kiso observatory in Japan (whose primary focus is on super-novas), and our video composited from the images taken from Cerro Tololo – whose credit of telescope stewardship can be found with Dr. Dan Reichart of UNC, Chapel Hill, as they hunt for the after glow of gamma ray bursts.

Video, as promised:

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Snippets

compiled by Arlene & David Kaplan

Colliding neutron stars - NPR

Colliding neutron stars – NPR

Astronomers Strike Gravitational Gold In Colliding Neutron Stars
For the first time, scientists have caught two neutron stars in the act of colliding, revealing that these strange smashups are the source of heavy elements such as gold and platinum…more

-BBC

-BBC

The place spacecraft go to die
China’s Tiangong-1 space station is currently out of control and expected to fall back to Earth next year. But not in the remote place where many other spacecraft end their days. Explorers and adventurers often look for new places to conquer…more

-NASA/JPL

-NASA/JPL

Nasa carbon space observatory ‘watches Earth breathe’
A Nasa satellite has provided remarkable new insights on how CO2 is moved through the Earth’s atmosphere. The Orbiting Carbon Observatory (OCO) tracked the behaviour of the gas in 2015/2016 – a period when the planet experienced a major El Niño event…more

-NASA/JPL


Astronomers Race to Study a Mystery Object From Outside Our Solar System
For the first time that we know, an interstellar visitor has zoomed through our solar system. The small space rock, tentatively called A/2017 U1, is about a quarter of a mile long and astronomers across the world are racing to study it before it departs just as quickly as it arrived…more

Sync your calendar with the solar system
Add the calendar on Google or iOS…more

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